Thread: beware Water in sub-fin

I had a problem in 9/08 with a 2006 CTSW. Water accumulated in the sub fin under the tail.
Dimpling of the plastic was the first symptom. About 3/4 Gal of water was drained
out (5 lb) at an arm of 150 in. The CG was still in the envelope.
I was careful not to get water in when washing the plane,
and used ComposiClean detergent.
I suspect rain got in, as the plane is not in a hangar.

This problem developed slowly; I started to flare
too high, did a hard landing, and bent the wheel attachments.

So, take extra care to check for water and the drain holes being clear.
I now carry pipe cleaners to probe the drains (and static port).

Bill Mc.

We've experienced the same problem on a 2005 CTSW. Water got in during a wash job. Unbekown to us, the drain hole was plugged. We noticed the sides of the "keel" started dimpling in and the structure seemed soft. The clue was the water droplet hanging on the bottom. Pushed a tiny screwdriver into the hole and whoosh...out came about two gallons of water. It had been sitting in the keel for about 10 days before we got it out, but the damage was done. An unfortunate mistake and lack of paying attention to detail. Lesson learned! Keep those drain holes clear!

Some of the drain holes are a little small and clog easily. The underfin could then accumulate water weight. More than one drain hole may be advisable if you leave your plane outside all the time. I would suggest you drill the existing hole out a bit more to make sure nothing will clog it in the future. If a drain hole seems clogged or too small then drill it open a tad more to allow debris to flow free and not get hung up.

Where are situated all the drain holes on a CT ? ( just to check )

Thanks